464 CALYPTR^EIDTE. 



Gdyptrxa Sinensis, Desh. Ann. Sc. Nat. vol. iii. (1824), p. 335, pi. 17, f. 1 , 2 

 Encycl. Meth. vol. ii. p. 175. — Brown, Illust. Conch 

 G.B.p. 60, pi. 20, f. 16, 18. 

 Patella muricata, Costa, Moll. Sicil. p. 124. 



„ vulgaris, Philippi, Moll. Sicil. vol. i. p. 119, and vol. ii. p. 93. 

 Infundibulum rectum (fossil), J. Sowerby, Min. Conch, pi. 97, fig. 3. 

 „ Sincnse (fossil), Morris, Cat. Brit. Fos. p. 148. 



This delicate shell is thin, semi-transparent, and of an 

 uniform white both within and without. It is nearly 

 circular at the base, is depressed-subconical, and has the 

 vertex nearly central, tapering to a small point, and 

 rapidly subspiral. The outer surface is rather dull, and 

 either almost smooth, or closely set with small very thin 

 and caducous vaulted scales, which latter is probably the 

 normal state, and the frequent smoothness the mere result 

 of abrasion. No other sculpture is obvious, but the lines 

 of growth are often strongly indicated. The interior is 

 highly polished, and has the margin perfectly entire ; 

 there is a remarkably fragile broad septum, which runs 

 obliquely and spirally from under the vertex, so as to 

 cover over about one fourth of the area of the lower 

 disc. This septum, which is more or less concave, and 

 only marked with the lines of growth, is attached to 

 the side of its arcuated outer edge, and is free and much 

 incurved at its inner edge, which latter is strengthened 

 by a more copious deposition of shelly matter, and 

 forms a kind of pseudo-columella : the terminal edge of it 

 is convex, and very nearly reaches to the basal level. The 

 diameter of the base rarely exceeds three quarters of an 

 inch. 



The animal is yellowish, or fawn white, with opaque 

 dots. The head is not very prominent, and is short, 

 terminating in a cleft or bilobed muzzle. On each side 

 of it is a thick cylindric rather short tentacle, bearing the 



